Many systems such as digital and mixed signal systems may include multiple similar units. For example, a mixed signal system such as a communication system (e.g., a 100 GHz coherent transceiver) may be subdivided into one or more sub-systems including analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and/or serializer-deserializers (SerDes). Each of the subsystems may, in turn, consist of a number of similar units. For instance, an ADC may be built with hundreds of (e.g., 512 or more) successive-approximation register (SAR) units. A serious concern in such multi-unit systems is the system-level effect of any failure in one or more of the units of the multi-unit system. For example, even one bad SAR unit in an ADC with multiple SAR units may significantly impact the effective number of bits (SNOB) of the ADC.